Silver halibe emulsions



i atenteci 6 UNITED STATES PATENT QFFICE 2,546,636 SILVER HALIDE envision Walter Dewey EBaIdsiefen, vrtucilen, Lduis John} son Conrad, New. Brunswick, and Richard Newton Linkhart, Menio Park, N. J., assignors to .E. I. an lont d'e Nemoojrs" 83 Company, Wilmin ton, Ilel'., a corporation of Delaware N6 Drawing.

Application June 17, 1948;

Serial No. 33,664

5 Claims.

thiosulfate, the amounts may range from 1.73 to 912 mg. per 486 g. of silver in the emulsions. Photographically equivalent amounts of other sulfur sensitizers can be used.

The gold, palladium and mercury salts are added to the colloid silver halide emulsions after the silver salts have been precipitated and the wate'r-solubl e salts have been removed. The set which have improved speed and contrast. A reand washed emulsion is liquefied, the small lated object is to produce such emulsions which 10 amount of sulfur sensitizer is added, and the have relatively low fog levels. A further object emulsion adjusted to a pH from 5.5 to 6.5. A is to produce such emulsions with relatively mixture of chlorauric acid, palljadium chloride available simple chemicals. Still otherobjfects and mercuric chloride is added to the emulsion will be apparent from the following description from an aqueous solution. The emulsion is then of the invention. digested fora suitable time to obtain the maxi- Ihe photographic emulsions of this invention mum sensitivity and coated onto a suitable supare' of the development type and consist of a port to form a thi1i1ight=sensitive layer. An opsilver halide suspension in a hydrophilic" colloid ti'cal sensitizing dye, e. g., a cyan-ins. carbobi-nding agent, e; g., gelatin, whi chcontains small cyanine, merocyanine, pseudocyanine, or styryl amounts of a sulfur sensitiz'er and very small 0 dye,- can be added to the emulsion prior to or subamounts of gold,- palladium and mercury. The sequent to digestion, if desired. sulfur sen-sitizer may be one of the naturally 0c The invention will be further illustrated but curring sulfur compounds which are present. in is not intended to be limited by the following exphotographic gelatin or they may be added sulainples. :fur compounds, e. g., sodium thiosulfate, sodium 2 Example I thiocyanate, allylthiourea, allyl isothiocyanate, J m; A silver halide dispersion in inert photographic The amount f m pauadium and mercury gelatin containing 7.5% silver iodide and 92.5% salts which may be added to the emulsions W111 silver bromide and a sensitizing dye was divided vary. Inthe case of thepreferred salts,chlorauric into samples equivalent 11191 of Silver amd (AUCIS.HC1.4H2O) is used in an amount of ides each. Additions as tabulated below were 1.34 to mg; palladium chloride (PdClz-ZHzO) m a the sampl'es were digesfi'd until they is used in an amount of 1.0 to 9.33 mg, and men reached the maximum light sensitivity- The curic chloride is used in an amount of 1 .32 to- Sumnjg emu 15in samplas W Coated on 1.97 mg. per 765 g. of silver nitrate used in makbase m a thm layer and drled Samples of 52nd ing the original emulsions or based on the silver fi1m e1ements were then exposed a type 13 the emulsion (1. e., 486 g.). The mol f gs me r I tQ- in a developer of the per cents of the gold, palladium and mercury as Q l' compositronz elements are respectively .0000723 1701300288 for N-methyl-para-aminophenol= sulfate g- 2.5 gold, 1300104 to .000975 for palladium-,and 000108 40 Hydroquinone g 310 to .000162 for mercury. Other salts can be used sodium sulfite (anhydrous) g 75.0 in chemically equivalent amounts. Borax g 5.0

The amount of sulfur sensitizer will also vary Water to 1 liter. depending on the: chemical constitution of the v for 9 minutes at 68 F. with the results listed in particular compound used. In the'caseof sodium the following. table:

ris this as... Molarcc with? cc. M ol gcc cc. speed Example II Grams N-methyl-para-aminophenol sulfate 0.8 Hydroquinone 1.0 Sodium sulfite (anhydrous) 90.0 Borax 3.0 Potassium bromide 0.1

Water to 1 liter for minutes at 68 with the results listed in the following table:

4; with the following adjuvants. The results are set forth in the following table:

[Adjuvauts are 6 l0- molar in 1310.]

Palladium Mercuric Chlorauric Relative chloride chloride Gamma Fog acid, co. m m speed This invention is not limited to the use of gelatin as the binding agent for the silver halides. On the contrary, other hydrophilic colloids can be used. Suitable colloids include agar-agar, polyclycuronic acids, zein, collodion, water-soluble cellulose derivatives, such as substantially hydrolyzed cellulose acetate, cellulose esters of hydroxy monocarboxylic acids, e. g., lactic or glycolic acids, alkali metal salts of cellulose esters of dicarboxylic acids, such as phthalic acid, polyvinyl alcohol, partially hydrolyzed polyvinyl acetate and interpolymers thereof with unsaturated Concentration 6 l0- Molar 5 222 Gem. Fog Nazszoi, Chlorauric Palladium Mercuric P cc. Acid, cc. Chloride, cc. Chloride. cc.

Example III A gelatino-silver iodobromide emulsion of the type disclosed in Example II was prepared using inert gelatin and the additions listed in the following table made. The emulsions were coated and tested as in Example II with the results tabulated below:

[All adjuvants are 6 10-= molar in 11 0.]

materials, such as styrene, maleic acid, etc., water-soluble polyvinyl ac-etals and other hydrophilic synthetic or natural resins and polymeric compounds. Suitable hydrophilic colloids of the above types are described in United States Patents 2,110,491, 2,276,322, 2,276,323, 2,286,215, and 2,211,323.

Sodium Palladium Mercuric Emul Chlorauric Relative No 301d, cm Chlggdf chlggide, speed Gam log 25 01 23 141 1. l1 14 23 22 76 79 06 23 7. 3 l6 4 214 1. 0S 06 7. 3 l6 4 20 45 01 Samples of the above emulsions were aged for a period of one week at 120 F. with the results given in the following table.

Ewample IV A silver iodobromide dispersion in photographic gelatin containing naturally occurring sulfur sensitizers containing 6.0 mol per cent silver iodide and 94 mol per cent silver bromide was An advantage of the invention is that it provides a simple and effective method of increasing the speed and contrast of photographic emulsions. A further advantage is that increases in speed are obtained which do not entirely disappear on aging. A still further advantage resides in the fact that increased speed and contrast are attained Without an undesirable increase in fog.

As many widely different embodiments of this invention can be made without departing from the spirit and scope thereof, it is to be understood that the invention is not to be limited except as defined by the claims.

What is claimed is:

1. A colloid silver halide emulsion containing water-soluble salts of gold, palladium and mercury in such proportions that the emulsion conp epa ed. c ated. and tested as in Example I bu tains .000723 to .000288 mol per cent of gold,

.000104 to .000975 mol per cent of palladium, and, .000108 to .000162 mol per cent of mercury, based on the silver.

2. A gelatin silver halide emulsion containing water-soluble salts of gold, palladium and mercury in such proportions that the emulsion contains .0000723 to .000288 mol per cent of gold, .000104 to .0009'75 mol per cent of palladium, and, .000108 to .000162 mol per cent of mercury based on the silver content.

3. A gelatinsilver iodobromide emulsion predominating in silver bromide containing watersoluble salts of gold, palladium and mercury in such proportions that the emulsion contains .0000723 to .000288 mol per cent of gold, .000104 to 000975 mol per cent of palladium, and 000108 to .000162 mol per cent of mercury, based on the silver.

4. A gelatin silver halide emulsion containing water-soluble salts of gold, palladium and mercury in such proportions that the emulsion contains .0000723 to .000288 mol per cent of gold, .000104 to .000975 mol per cent of palladium, and

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,059,642 Kankelwitz Nov. 3, 1936 2,448,060 Smith et a1 Aug. 31, 1948 

1. A COLLOID SILVER HALIDE EMULSION CONTAINING WATER-SOLUBLE SALTS OF GOLD, PALLADIUM AND MERCURY IN SUCH PROPORTIONS THAT THE EMULSION CONTAINS .000723 TO .000288 MOL PER CENT OF GOLD, .000104 TO .000975 MOL PER CENT OF PALLADIUM, AND, .000108 TO .000162 MOL PER CENT OF MERCURY, BASED ON THE SILVER. 